/// <summary>/// 檢測URL地址是否可以訪問/// </summary>/// <param name="Url">URL地址(以http://開頭)</param>/// <returns>返回OK</returns>/// <example>IsUrlVist("http://www.baidu.com")</example>public static string IsUrlVisit(string Url){    string reVlue = null;    try    {        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(new Uri(Url));        request.Timeout = 30;      //超時時間        ServicePointManager.Expect100Continue = false;        ((HttpWebResponse)request.GetResponse()).Close();        reVlue = "OK";    }    catch (WebException ex)    {        reVlue = ex.ToString();    }    return reVlue;}